Objectives: To evaluate changes on bilateral and unilateral jump performance and frontal knee projection angle after an implementation of a core strength program in female handball players. Equipment and methods: This is a randomized controlled trial study. A total of 20 participants [age = 17.2 (1.9) years, height = 1.7 (0.1) m, weight = 62.8 (7) kg ] were recruited and split in: a core training group and a control group. The core training group participated in 8 weeks in-season of a core strength program (2 times/week). Pre- and post-intervention jump height, contact time and reactive strength index were collected during bilateral and unilateral drop vertical jumps. Frontal knee projection angle was measured only at unilateral drop jumps. Results: Core training group increased the bilateral jump height by 18.8% and showed a statistically significant difference in reactive strength index from pre-intervention [0.07 (0.03)] to post-intervention [0.10 (0.04)]. The core training group also improved the unilateral jump height by 20%, but only at the non-dominant leg. This improvement was accompanied by a statistically significant decreased in the frontal knee projection angle from pre-intervention [13.8 (7.38) degrees] to post-intervention [9.3 (6.09) degrees]. Statistical significant difference was set at p ˂0.05. Conclusion: A core strength training increased jump performance and it could play a role in ACL injury prevention programs in female team players.